$\left(3s^2t^2\right)\left(-9s^6t^2+5s^7t^4+8st^2\right)$

$3x^3y^3\left(2x^2y^4\right)$

$\sqrt[4]{\frac{1}{81}}+\sqrt[3]{\frac{1}{27}}+\sqrt{\frac{1}{9}}$

$2tan2x-1=0$

$1-\tan\left(x\right)^2.\cos\left(x\right).\sin\left(x\right)$

$2x+y+2z=6$

$x^4+2x^2-y;\:x=2;\:y=0$